Savannah River Site (copy)

An aerial view of the nixed Mixed Oxide Fuel Fabrication Facility and, in the distance, Plant Vogtle near Waynesboro, Georgia.

The National Nuclear Security Administration recently approved a crucial next step for a project designed to dispose of metric tons of excess defense plutonium in the U.S.

The semiautonomous U.S. Department of Energy agency late last year signed off on the so-called "Critical Decision 1" for the Surplus Plutonium Disposition project, the Savannah River Site-intensive alternative for the mothballed and never-completed Mixed Oxide Fuel Fabrication Facility.

The approval was mentioned at the bottom of a Jan. 10 weekly report from the Defense Nuclear Facilities Safety Board. The NNSA confirmed the matter to the Aiken Standard on Thursday morning.

A cost range of $448 million to $620 million was approved for the disposition project by the National Nuclear Security Administration's project risk and management committee, a senior NNSA spokesperson told the Aiken Standard.

Getting to and achieving Critical Decision 1 involves evaluating a still-in-its-infancy project, including conceptual designs and rough cost estimates. A project is effectively complete and ready to go at Critical Decision 4.

The Savannah River Site management and operations contractor, currently Fluor-led Savannah River Nuclear Solutions, will handle all phases of the project's execution, the same spokesperson said. Savannah River Nuclear Solutions is also spearheading the preparation for and buildout of plutonium pit production capabilities (the forging of nuclear weapon cores) at the site.

An SRNS spokesperson confirmed the contractor's role Thursday afternoon.

The Surplus Plutonium Disposition project – to begin operations in earnest in 2028, according to an NNSA strategic roadmap – is more widely known as the dilute-and-dispose campaign, a cross-country plutonium disposition odyssey.

Dilute-and-dispose in this case involves taking plutonium, mixing it with other inhibiting materials, packing the mixture into secure containers and trucking those to the Waste Isolation Pilot Plant in southeastern New Mexico for burial.

It could take decades to process and get rid of the 34 metric tons of deemed-surplus plutonium once meant for conversion at the Mixed Oxide Fuel Fabrication Facility, according to an interim report issued in late 2018. That's a timeframe susceptible to funding fluctuations and public perception hiccups.

Dilute-and-dispose – the favored approach of NNSA chief Lisa Gordon-Hagerty and former Energy Secretary Rick Perry – has been demonstrated on a smaller tranche of plutonium being handled by the Energy Department's nuclear cleanup office, Environmental Management, the Savannah River Site landlord.

Dilute-and-dispose is less complex than the MOX option, which involves turning weapons-grade plutonium into nuclear fuel, the 2018 interim report noted. The cost-bloated, multibillion-dollar Mixed Oxide Fuel Fabrication Facility project was nixed under Perry's watch.

In a June 2019 interview with the Aiken Standard, Gordon-Hagerty affirmed her dedication to the dilute-and-dispose approach: "But nonetheless, our plan is to dilute-and-dispose of 34 metric tons of excess plutonium, and that is our stance, and that will continue to be our stance."

The Surplus Plutonium Disposition project itself demands new equipment be installed at the Savannah River Site, a sprawling nuclear reserve near New Ellenton where metric tons of plutonium are already kept.

Most of the weapons-grade plutonium once destined for MOX never made it to the Savannah River Site, an NNSA official previously told the Aiken Standard. A majority is stored elsewhere.

Colin Demarest covers the Savannah River Site, the U.S. Department of Energy, the National Nuclear Security Administration and government in general. Follow him on Twitter: @demarest_colin